Color-blindness in its relation to accidents by rail and sea
A government report published in Washington in 1878 by the Swedish physiologist Frithiof Holmgren, written for railway and maritime authorities to explain how colour blindness relates to accidents at rail and sea. Its pictures are plain diagrams of overlapping bell-shaped curves plotted along a labelled spectrum axis, numbered one to three, marked with letters R, O, Y, G, B, V, showing how sensitivity to each colour differs between observers; a designer could borrow the clean graph layout and the rainbow-letter axis as a simple scientific chart motif.
